This is done using the speed of the vehicle U, which is assumed constant:

The other parameters entering the optical theory, such as different indices of refraction, layer thicknesses and light wavelengths, are assumed constant with some uncertainty.

This is because both are assumed constant.

In real stock prices, volatility changes over time (possibly stochastically), but in GBM, volatility is assumed constant.

In the above table, geopotential height is calculated from a mathematical model in which the acceleration due to gravity is assumed constant.

The quantity can be assumed constant in a wide range of incidence.

Big blocks mean there is a low gradient, and therefore low discharge (hydraulic conductivity is assumed constant here).

The UV Index forecast values are assumed constant over the hour of each of the 24 1-hour forecasts.

The Roe method consists of finding a matrix that is assumed constant between two cells.

However to simplify the apparatus the radiometer will not be used and the light intensity will be assumed approximately constant.